Revenue Recognition (Schedule Of Sales By Type Of Product) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 29, 2018 USD ($)	Sep. 29, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jul. 01, 2017 USD ($)	Apr. 01, 2017 USD ($)	Dec. 29, 2018 USD ($) segment	Dec. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Disaggregation of Revenue [Line Items]
Number of reportable segments | segment									1
Total net sales	$ 892,988	$ 869,076	$ 871,100	$ 876,106	$ 883,748	$ 854,261	$ 876,569	$ 852,229	$ 3,509,270	$ 3,466,807	$ 3,136,720
Sales Revenue, Net [Member] | Product Concentration Risk [Member]
Disaggregation of Revenue [Line Items]
Total net sales									$ 3,509,270	$ 3,466,807	$ 3,136,720
Concentration percent									100.00%	100.00%	100.00%
Grocery [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member]
Disaggregation of Revenue [Line Items]
Total net sales									$ 3,063,218	$ 3,041,481	$ 2,736,596
Concentration percent									87.30%	87.70%	87.30%
Pharmacy [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member]
Disaggregation of Revenue [Line Items]
Total net sales									$ 314,584	$ 309,079	$ 298,875
Concentration percent									9.00%	8.90%	9.50%
Fuel [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member]
Disaggregation of Revenue [Line Items]
Total net sales									$ 125,993	$ 109,467	$ 94,907
Concentration percent									3.60%	3.20%	3.00%
Manufacturing [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member]
Disaggregation of Revenue [Line Items]
Total net sales									$ 5,475	$ 6,780	$ 6,342
Concentration percent									0.10%	0.20%	0.20%